Quantum mechanical study of the vibrational–rotational structure of [O2(3Σg-)]2. Part I

Abstract

Starting with a previously defined potential energy surface for the singlet ground state of [O₂(³Σ_g^-)]₂, we calculate the bound rovibrational states of the dimer for J⩽6 by solving the secular problem over the exact Hamiltonian, considering the two monomers as rigid. It follows the LC-RAMP treatment of Tennyson and van der Avoird, which includes centrifugal distortions and Coriolis interactions, using a product basis of analytical radial functions (Morse oscillators) and angular momentum eigenfunctions. The symmetries of the permutation-inversion group G₁₆ are used to reduce the size of the calculations. We find that the (O₂)₂ dimer has 26 bound vibrational levels (J=0). The dissociation energy of the ground vibrational level, D₀″=73.2 cm^-1, is found to be in good agreement with previously predicted experimental values.